You can share your last drink of water with your clock....and get a free energy ride for 12-14 weeks. No batteries, no chemicals, no electricity.

What’s the secret? This water clock runs off a galvanic cell battery. A cathode or positive metal (such as copper) and an anode or negative metal (such as zinc) are immersed in an electrolyte solution. The water serves as the electrolyte solution, which allows the transfer of electrons between the two metals, resulting in an electric cell.

A built-in solar-cell with a rechargeable battery that's described as having a life of 8 years. This clock sets itself to the time signal from the US atomic clock at Fort Collins, CO. The really cool thing is that it automatically adjusts for Daylight Savings Time and standard time. Besides the larger display of time, the clock shows the date, day of the week and room temperature at the bottom.

A projection clock with a unique feature...a smart sensor that detects room brightness and automatically turns off the projection to save energy. It's powered by the sun and has a detachable solar panel! Six hours of sunlight powers the clock for 2 months.